Preparation of polydopamine modified urchin-like titanate nanospheres adsorbent and its application in immunoglobulin G enrichment

Abstract

The application relates to the preparation and application of nanometer materials and the field of nanometer biological analysis, and particularly relates to the preparation and application of a solid-phase extraction material for enriching immunoglobulin G. The application takes the urchin-shaped titanate nanometer microsphere as a carrier of a solid-phase extraction adsorbent, modifies polydopamine on the surface of the carrier, further obtains an adsorbent which can be applied to the enrichment of immunoglobulin G, and explores and evaluates the adsorption / desorption of immunoglobulin G. The method comprises the following steps: synthesizing inorganic material titanate nanometer flower and modifying polydopamine on the surface of the inorganic material by using a polymerization reaction to construct a solid-phase extraction adsorbent which has hydrophilic interaction with immunoglobulin G, investigating influence factors such as pH and salt concentration, and analyzing protein mixed solution and actual human serum samples.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of preparation and application of nanomaterials and nanobiological analysis, in particular to the application of urchin-like titanate nanomicrospheres modified by polydopamine as adsorbents in the enrichment of immunoglobulin G in biomedical research. BACKGROUND

[0002] Proteins are not only the material basis of life, but also essential nutrients for the human body. The internal organs, blood, brain, nerves, nails, hair, etc. of the human body are all composed of proteins. Proteins also participate in a variety of important physiological functions such as regulation, catalysis, transport, storage, protection, etc., to ensure the growth, development, heredity, reproduction and repair of damaged tissues of the body.

[0003] Immunoglobulin is the most important component of the human immune system, and the content of immunoglobulin is closely related to the occurrence of diseases. Immunoglobulin G is the main antibody type in blood and extracellular fluid, and its content in human serum is the highest. It is the main component of antibacterial, antitoxin and antiviral antibodies. Moreover, it is the only immunoglobulin that can pass through the placental barrier, and plays an important role in resisting infection for newborns of mammals. Monitoring immunoglobulin G can help to judge and identify infectious diseases, immune proliferative diseases and immune deficiency diseases, etc. Clinically, the determination of the content level of immunoglobulin G is generally considered to be an indication of the immune status of the body to specific pathogens, and is used to prevent influenza, rheumatic diseases, resist cancer and other diseases.

[0004] However, an important challenge for immunoglobulin G enrichment is the presence of many other interfering proteins in complex biological samples. Therefore, it is of obvious importance to explore a method for efficiently enriching immunoglobulin G. In the past decade, many protein enrichment methods have been developed based on the interaction between proteins and materials, such as enrichment of target proteins through hydrophilic interaction, chelation, electrostatic force, hydrogen bonding, etc. In addition, various enrichment methods have also been developed and used, such as protein separation and enrichment by liquid-liquid extraction, precipitation, electrophoresis, ultrafiltration, solid-phase extraction, etc. Among them, solid-phase extraction is mostly used to selectively adsorb target substances in the matrix by using solid adsorbents to generate interaction forces, thereby completing the separation and enrichment of target substances. Since solid-phase extraction has high separation efficiency, is reliable, consumes less reagent, is simple to operate, and has high selectivity and recovery rate for target substances, the present application separates immunoglobulin G from complex samples by solid-phase extraction.

[0005] Titanate nanomaterials are often used as photocatalysts, humidity sensors, high dielectric constant devices and nanobiomaterials due to their excellent physical and chemical properties. In recent years, titanate nanomaterials have been gradually developed and used in the enrichment of biomacromolecules. There are many methods for preparing titanate nanomaterials, and the current main methods include solid phase method, coprecipitation method, sol-gel method and hydrothermal method. The polydopamine modified urchin-like titanate nanomicrospheres are prepared by the hydrothermal method. SUMMARY

[0006] The purpose of the present application is to overcome the limitations of the immunoglobulin G enrichment method and to expand the application range of titanate nanomaterials. A preparation method and application direction of polydopamine modified titanate nanomicrospheres are provided. The prepared titanate nanomicrospheres have an open mesoporous morphology and a high specific surface area. Since polydopamine contains a large number of hydrophilic groups, it can form hydrophilic interactions with proteins rich in hydrophilic groups, so it can selectively adsorb immunoglobulin G. The titanate nanomicrospheres prepared by the present application can realize the enrichment of immunoglobulin G in complex protein samples as a solid phase extraction adsorbent, and can realize the enrichment of immunoglobulin G in complex biological samples (human serum).

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0008] The preparation method of the polydopamine modified urchin-like titanate nanomicrosphere adsorbent (PDA-UTMS) comprises the following process steps:

[0009] (1) Synthesis of sodium titanate nanotubes (Na-TNT): titanium dioxide P25 is used to prepare Na-TNT by hydrothermal reaction in NaOH solution;

[0010] (2) Preparation of urchin-like sodium titanate nanomicrospheres (Na-UTMS): Na-UTMS is synthesized by solvothermal method using Na-TNT obtained in step (1); Na-TNT and H2O2 are ultrasonically stirred in NaOH solution to obtain a uniform mixed solution; the mixed solution is transferred to a high-pressure reaction kettle for solvothermal reaction, and after the reaction is completed, it is naturally cooled to room temperature, washed with deionized water for 4-5 times, and vacuum dried to obtain urchin-like sodium titanate nanomicrospheres (Na-UTMS);

[0011] (3) Preparation of protonated urchin-like titanate nanomicrospheres (H-UTMS): Na-UTMS obtained in step (2) is subjected to proton exchange with HNO3 to synthesize H-UTMS;

[0012] (4) Preparation of polydopamine modified urchin-like titanate nanomicrosphere adsorbent (PDA-UTMS): H-UTMS obtained in step (3) is used to modify polydopamine on the surface to synthesize PDA-UTMS; specifically, H-UTMS is dispersed in a tris(hydroxymethyl)aminomethane (Tris) solution and mixed with a dopamine aqueous solution, stirring is performed at room temperature, after the reaction is completed, washing is performed with deionized water, and polydopamine modified urchin-like titanate nanomicrosphere (PDA-UTMS) is obtained after vacuum drying.

[0013] In the step (1), 2 g of P25 is placed in 40 mL of 10-15 M NaOH aqueous solution, ultrasonic stirring is performed for 5-10 min, then it is transferred to a polytetrafluoroethylene-lined stainless steel reaction kettle and sealed; the reaction kettle is placed in an oven, heating treatment is performed at 100-120℃ for 24-48 h, after the reaction is completed, natural cooling is performed in air, Na-TNT precipitate is generated, centrifugation, washing and drying are performed.

[0014] In the step (2), 0.2 g of Na-TNT and 1.5 mL of H2O2 (30%) are added to 40 mL of 0.5-1.5 M NaOH aqueous solution for solvothermal reaction, the reaction temperature is 130-150℃, and the reaction time is 10-14 h.

[0015] In the step (4), 10 mL of 0.5-1.5 mg mL -1 of a dopamine aqueous solution is slowly added to a mixed solution of 50-100 mg of H-UTMS and 10 mL of 0.1 mg mL -1 of Tris, and the stirring time is 2-4 h.

[0016] The application further provides application of the polydopamine modified urchin-like titanate nanomicrosphere adsorbent (PDA-UTMS) in enrichment of immunoglobulin G. The specific application method comprises the following steps:

[0017] (1) Adsorption of PDA-UTMS to immunoglobulin G: the hydrophilic groups of polydopamine on PDA-UTMS and the hydrophilic groups of immunoglobulin G are used to perform selective adsorption of immunoglobulin G from a complex sample through hydrophilic interaction.

[0018] (2) Elution of immunoglobulin G from PDA-UTMS: the interaction between the eluent ammonia and the immunoglobulin G combined on the microspheres is used to elute the immunoglobulin G adsorbed on PDA-UTMS, so as to achieve the purpose of enrichment of immunoglobulin G in a complex sample.

[0019] In the process of enriching immunoglobulin G: 100 μL of 10 mg mL -1PDA-UTMS was placed as adsorbent in 900 μL of 0.1 mg mL -1 of immunoglobulin G in 0.01-0.05 M Tris-HCl solution. The adsorption time was 30-60 min. The elution time was 30-60 min. The adsorption and elution were detected by UV / Vis spectrophotometer.

[0020] In the process of enriching immunoglobulin G in the mixed solution of proteins: 100 μL of 10 mg mL -1 PDA-UTMS, 50 μL of 2 mg mL -1 immunoglobulin G, 50 μL of 2 mg mL -1 bovine serum albumin and 800 μL of 0.01-0.05 M Tris-HCl with pH = 7 were mixed to form a mixed protein solution. The adsorption time was 30-60 min. The elution liquid was 0.5% (m / v) ammonia water, and the elution time was 30-60 min. The enrichment effect was detected by polyacrylamide gel electrophoresis (SDS-PAGE).

[0021] In the process of enriching immunoglobulin G in human serum: 100 μL of 10 mg mL -1 PDA-UTMS, 10 μL of serum and 890 μL of 0.01-0.05 M Tris-HCl with pH = 7 were mixed. The adsorption time was 30-60 min. The elution liquid was 0.5% (m / v) ammonia water, and the elution time was 30-60 min. The enrichment effect was detected by polyacrylamide gel electrophoresis (SDS-PAGE).

[0022] The nanometer microspheres adopted in the application have good stability, and due to the open mesoporous morphology and high specific surface area, they have more active sites. The application studies the adsorption of immunoglobulin G by polydopamine modified titanate nanometer microspheres under different pH values and different ionic strengths, investigates the elution of immunoglobulin G by different elution liquids, and explores the best conditions for the enrichment of immunoglobulin G by polydopamine modified titanate nanometer microspheres. The application is successfully applied to the enrichment of immunoglobulin G in the mixed solution of immunoglobulin G and bovine serum albumin and the enrichment of immunoglobulin G in human serum.

[0023] Compared with the prior art, the advantages of the polydopamine modified urchin-like titanate nanometer microsphere adsorbent prepared by the application and its application in the enrichment of immunoglobulin G are as follows:

[0024] 1. The polydopamine modified urchin-like titanate nanometer microspheres are prepared by a hydrothermal method. Compared with the traditional solid-phase preparation method, the material prepared by this method has a light degree of agglomeration and can be synthesized at a lower temperature.

[0025] 2. Compared with the traditional immunoglobulin G enrichment method, the efficiency is high, the reagent consumption is low, and the operation is simple;

[0026] 3. The nano-microsphere prepared by the method has good stability, and due to the open mesoporous morphology and high specific surface area, the nano-microsphere has more active sites and has better enrichment capacity for immunoglobulin G;

[0027] 4. The solid-phase extraction adsorbent prepared by the method can enrich target proteins, and realizes the enrichment of immunoglobulin G in complex protein samples and human serum. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Synthesis diagram of polydopamine modified urchin-like titanate nanomicrosphere adsorbent (PDA-UTMS);

[0029] Figure 2 Scanning electron microscope image of PDA-UTMS;

[0030] Figure 3 Infrared spectrum of PDA-UTMS;

[0031] Figure 4 Adsorption effect of PDA-UTMS on different proteins;

[0032] Figure 5 Effect of pH on adsorption of PDA-UTMS on BSA and IgG;

[0033] Figure 6 Effect of ionic strength on adsorption of PDA-UTMS on IgG;

[0034] Figure 7 Elution of IgG using different elution solutions;

[0035] Figure 8 Electrophoresis diagram of enrichment of IgG in a protein mixed solution by PDA-UTMS;

[0036] Figure 9 Electrophoresis diagram of enrichment of IgG in human serum by PDA-UTMS. DETAILED DESCRIPTION

[0037] The specific embodiments of the present application will be described in detail below in combination with the drawings and examples.

[0038] Example 1

[0039] Preparation of polydopamine modified urchin-like titanate nanomicrosphere adsorbent (PDA-UTMS) includes the following steps:

[0040] Step 1, Solvothermal synthesis of Na-TNT: Na-TNT was prepared by hydrothermal reaction of titania P25 in NaOH solution. 2 g P25 was put into 40 mL 10 M NaOH aqueous solution, after ultrasonic stirring for 5 min, it was transferred into a 50 mL polytetrafluoroethylene inner stainless steel reactor and sealed. The reactor was placed in an oven, heated at 120 °C for 24 h, and naturally cooled in air, resulting in Na-TNT precipitates. These precipitates were separated from the solution by centrifugation, followed by washing with deionized water several times to remove excess NaOH, and then dried in vacuum at 60 °C.

[0041] Step 2, Solvothermal synthesis of Na-UTMS: Na-UTMS was prepared by hydrothermal reaction of Na-TNT with H2O2 in NaOH solution. 0.2 g Na-TNT and 1.5 mL H2O2 (30%) were added to 40 mL 1 M NaOH aqueous solution, after ultrasonic stirring for 5 min, it was transferred into a 50 mL polytetrafluoroethylene inner stainless steel reactor, sealed. The reactor was placed in an oven, heated at 150 °C for 12 h, and naturally cooled in air, resulting in Na-UTMS precipitates. These precipitates were separated from the solution by centrifugation, followed by washing with deionized water several times to remove excess NaOH, and then dried in vacuum at 60 °C.

[0042] Step 3, Proton exchange synthesis of H-UTMS: H-UTMS was prepared by proton exchange of Na-UTMS in 1 M HNO3 solution, stirring for 12 h, and centrifugation. The proton exchange process was repeated once, and then washed with deionized water for 4-5 times. The obtained H-UTMS product was dried in vacuum at 60 °C.

[0043] Step 4, Surface modification of nanospheres with polydopamine: 10 mL 1 mg mL -1 of dopamine aqueous solution was slowly added to the mixture of 50 mg H-UTMS and 10 mL 0.1 mg mL -1 of Tris, stirring for 2 h, centrifugation, and then washing with deionized water for 4-5 times, to obtain PDA-UTMS, which was dried in vacuum at 60 °C. The preparation process of PDA-UTMS is shown in Figure 1 The morphology of the prepared PDA-UTMS was observed by su8020 Hitachi scanning electron microscope, from Figure 2 which it can be seen that PDA-UTMS is in the form of sea urchin. PDA-UTMS was characterized by Nicolet 6700 Fourier infrared spectrometer of American Nicolet Company, from Figure 3 which it can be seen that the peak at 3000 to 3500 cm -1 corresponds to the vibration of O-H bond, and the peak at 400 cm -1The peaks on the left and right belong to the stretching vibration of Ti-O bond. The test was performed by HORIBA EX-350 energy dispersive X-ray analysis device. As can be seen from the element content of PDA-UTMS and H-UTMS in Table 1, after the modification of polydopamine, a large amount of C element appeared, which proved that the polydopamine was successfully modified on the surface of titanate nanomicrosphere, which further proved the successful synthesis of PDA-UTMS.

[0044] Table 1 Composition analysis table of PDA-UTMS by X-ray energy spectrometer

[0045]

[0046] Example 2

[0047] The enrichment of the polydopamine modified urchin-like titanate nanomicrosphere adsorbent (PDA-UTMS) on different protein samples includes the following steps:

[0048] Step 1, weigh a certain amount of polydopamine modified urchin-like titanate nanomicrosphere adsorbent (PDA-UTMS) into deionized water, and after ultrasonic treatment, 10 mg mL -1 of material suspension is obtained. Take 100 μL of 10 mg mL -1 of the suspension and mix it with 900 μL of 0.1 mg mL -1 of immunoglobulin G, bovine serum albumin (BSA), ovalbumin (Ova) and hemoglobin (Hb) respectively, and tris(hydroxymethyl) aminomethane-hydrochloric acid (Tris-HCl, 0.05 M, 800 μL, pH = 7.0) buffer solution to prepare a mixed solution.

[0049] Step 2, the mixed solution of step 1 is shaken on a shaker at room temperature for 60 min to promote the adsorption of proteins on the surface of the material. Then centrifuge at 5000 rpm for 5 min, collect the supernatant, and use ultraviolet / visible spectrophotometer to detect the concentrations of immunoglobulin G, bovine serum albumin, hemoglobin and ovalbumin before and after the adsorption of the adsorbent, and calculate the adsorption rate. The results are shown in Figure 4 , where the abscissa is immunoglobulin G, bovine serum albumin, hemoglobin and ovalbumin, and the ordinate is the adsorption rate. The results show that the adsorption rate of polydopamine modified urchin-like titanate nanomicrosphere on immunoglobulin G, bovine serum albumin, hemoglobin and ovalbumin is 96.0%, 38.8%, 68.5%, 72.0% respectively, which indicates that the prepared PDA-UTMS has good adsorption capacity for immunoglobulin G.

[0050] Example 3

[0051] Effect of pH on the enrichment of immunoglobulin G by polydopamine modified urchin-like titanate nanospheres adsorbent (PDA-UTMS), comprising the following steps

[0052] Step 1, weigh a certain amount of PDA-UTMS into deionized water, and after ultrasonic treatment, obtain a 10 mg mL -1 suspension of the material. Take 100 μL of the 10 mg mL -1 suspension and mix it with 900 μL of 0.1 mg mL -1 immunoglobulin G and Tris-HCl (0.05 M, pH = 7.0) buffer solution with different NaCl concentrations (0.1, 0.3, 0.4, 0.6, 0.8, 1.0 mol L -1 ) to prepare a mixed solution.

[0053] Step 2, shake the mixed solution of step 1 on a shaker at room temperature for 60 min to promote the adsorption of proteins on the material surface. Then centrifuge at 5000 rpm for 5 min, collect the supernatant, and use an ultraviolet / visible spectrophotometer to detect the concentration of immunoglobulin G before and after adsorption by the adsorbent, and calculate the adsorption rate. The detection results are shown in Figure 5 , where the abscissa is pH and the ordinate is the adsorption rate. The results show that the adsorption rate of PDA-UTMS for immunoglobulin G is the highest at pH = 7.

[0054] Example 4

[0055] Effect of ionic strength on the enrichment of immunoglobulin G by polydopamine modified urchin-like titanate nanospheres adsorbent (PDA-UTMS), comprising the following steps:

[0056] Step 1, weigh a certain amount of PDA-UTMS into deionized water, and after ultrasonic treatment, obtain a 10 mg mL -1 suspension of the material. Take 100 μL of the 10 mg mL -1 suspension and mix it with 900 μL of 0.1 mg mL -1 immunoglobulin G and Tris-HCl (0.05 M, pH = 7.0) buffer solution with different NaCl concentrations (0.1, 0.3, 0.4, 0.6, 0.8, 1.0 mol L -1 ) to prepare a mixed solution.

[0057] Step 2, shake the mixed solution of step 1 on a shaker at room temperature for 60 min to promote the adsorption of proteins on the material surface. Then centrifuge at 5000 rpm for 5 min, collect the supernatant, and use an ultraviolet / visible spectrophotometer to detect the concentration of immunoglobulin G before and after adsorption by the adsorbent, and calculate the adsorption rate.

[0058] Test results as follows Figure 6 As shown in the figure, the horizontal axis represents the concentration of NaCl, and the vertical axis represents the adsorption rate. The results show that the adsorption rate decreases with increasing ionic strength.

[0059] Example 5

[0060] The elution of immunoglobulin G from polydopamine-modified sea urchin-shaped titanate nanospheres (PDA-UTMS) includes the following steps:

[0061] Step 1: Weigh a certain amount of PDA-UTMS and add it to deionized water. After sonication, obtain 10 mg / mL. -1 The material suspension. Take 100 μL of 10 mg mL... -1 The suspension was placed in 900 μL of 0.1 mg / mL solution. -1 The mixture was prepared by mixing immunoglobulin G in Tris-HCl (0.05M, pH=7.0) buffer solution.

[0062] Step 2: The mixture from Step 1 was shaken on a shaker at room temperature for 60 min to promote protein adsorption on the material surface. Immunoglobulin G adsorbed by the adsorbent was then centrifuged at 5000 rpm for 5 min, and treated with 0.5% (m / v) ammonia water and 0.1 mol L⁻¹ ammonia solution, respectively. -1 Acetic acid, 0.1 mol L -1 Immunoglobulin G was eluted with imidazole and BR buffer (pH=10) for 60 min. The elution was monitored using a UV / Vis spectrophotometer, and the results are as follows: Figure 7 As shown, different elution reagents elute IgG differently. The highest recovery rate (92.3%) was observed when using 0.5% (m / v) ammonia solution, which may be related to the competitive hydrophilicity of ammonia solution towards IgG. Therefore, 0.5% ammonia solution was used as the eluent.

[0063] Example 6

[0064] The enrichment of immunoglobulin G in a mixed protein solution using polydopamine-modified sea urchin-shaped titanate nanospheres (PDA-UTMS) comprises the following steps:

[0065] Step 1: Weigh a certain amount of PDA-UTMS and add it to deionized water. After sonication, obtain 10 mg / mL. -1 The material suspension. Take 100 μL of 10 mg mL... -1 The suspension was prepared with bovine serum albumin and immunoglobulin G at a concentration of 0.1 mg / mL. -1 The mixture was prepared by mixing in a Tris-HCl (0.05M, pH=7.0) buffer solution.

[0066] Step 2, the mixture of step 1 was shaken on a shaker for 60 min at room temperature to promote the adsorption of proteins on the surface of the material. Then centrifuged at 5000 rpm for 5 min, the supernatant was collected, and then the PDA-UTMS combined with IgG was eluted with 0.5% (m / v) ammonia water, the elution was carried out for 60 min, and the eluate was collected. The solution after PDA-UTMS adsorption and elution was detected by SDS-PAGE. The enrichment results are shown in Figure 8 Figure 2: Lane 1 is the standard Maker lane, with units of kDa; Lane 2 is the supernatant of the mixed solution of IgG and BSA after adsorption by PDA-UTMS; Lane 3 is the eluate of PDA-UTMS combined with IgG eluted by ammonia water; Lane 4 is the standard of the mixed solution of 0.1 mg mL -1 of IgG and BSA. It can be seen from the figure that the bands corresponding to the heavy chain and light chain of IgG in Lane 4 in Lane 2 are obviously lighter, which shows that PDA-UTMS material can effectively enrich IgG in the mixed solution of bovine serum albumin and immunoglobulin G.

[0067] Example 7

[0068] Enrichment of immunoglobulin G in 100-fold diluted human serum by polydopamine modified urchin-like titanate nanomicrospheres adsorbent (PDA-UTMS), including the following steps:

[0069] Step 1, weigh a certain amount of PDA-UTMS into deionized water, mix 100 μL of 10 mg mL -1 PDA-UTMS solution, 10 μL of serum and 890 μL of 0.05 M Tris-HCl with pH = 7 to make a mixed solution.

[0070] Step 2, the mixture of step 1 was shaken on a shaker for 60 min at room temperature to promote the adsorption of proteins on the surface of the material. Then centrifuged at 5000 rpm for 5 min, the supernatant was collected, and then the PDA-UTMS combined with IgG was eluted with 0.5% (m / v) ammonia water, the elution was carried out for 60 min, and the eluate was collected. The solution after PDA-UTMS adsorption and elution was detected by SDS-PAGE. The enrichment results are shown in Figure 9 Figure 2: Lane 1 is the standard Maker lane, with units of kDa; Lane 2 is the supernatant of the mixed solution of IgG and BSA after adsorption by PDA-UTMS; Lane 3 is the eluate of PDA-UTMS combined with IgG eluted by ammonia water; Lane 4 is the standard of the mixed solution of 0.1 mg L -1IgG standard; lane 4 is the supernatant after the human serum is adsorbed by PDA-UTMS; lane 5 is the eluent after the PDA-UTMS combined with IgG is eluted by ammonia. The band corresponding to the IgG heavy chain in the IgG standard in lane 3 exists after the enrichment of PDA-UTMS from lane 5, which proves that the nano material can enrich immunoglobulin G from serum.

Claims

1. A method for preparing a polydopamine-modified urchin-like titanate nanomicrosphere adsorbent, characterized in that, The polydopamine modified urchin-like titanate nanomicrosphere adsorbent is used for preparing an immunoglobulin G enrichment material, and the process steps are as follows: (1) Synthesis of sodium titanate nanotubes: titanium dioxide P25 is used to prepare sodium titanate nanotubes by a hydrothermal reaction in a NaOH solution; (2) Preparation of urchin-like sodium titanate nanomicrospheres: the sodium titanate nanotubes obtained in step (1) are used to synthesize urchin-like sodium titanate nanomicrospheres by a solvothermal method; specifically, the sodium titanate nanotubes are ultrasonically stirred with 30% H2O2 in a 0.5-1.5 M NaOH solution to obtain a uniform mixed solution, the mixed solution is transferred into a high-pressure reaction kettle for a solvothermal reaction, the reaction temperature is 130-150 DEG C, the reaction time is 10-14 h, after the reaction is completed, the reaction kettle is naturally cooled to room temperature, the product is washed with deionized water for 4-5 times, and vacuum drying is performed to obtain urchin-like sodium titanate nanomicrospheres; (3) Preparation of protonated urchin-like titanate nanomicrospheres: the urchin-like sodium titanate nanomicrospheres obtained in step (2) are subjected to proton exchange with HNO3 to obtain protonated urchin-like titanate nanomicrospheres; (4) Preparation of polydopamine modified urchin-like titanate nanomicrosphere adsorbent: the protonated urchin-like titanate nanomicrospheres obtained in step (3) are used to modify polydopamine on the surface to obtain the polydopamine modified urchin-like titanate nanomicrospheres; specifically, the protonated urchin-like titanate nanomicrospheres are dispersed in a tris(hydroxymethyl) aminomethane solution and mixed with a dopamine aqueous solution, stirring is performed at room temperature, after the reaction is completed, the product is washed with deionized water, and vacuum drying is performed to obtain the polydopamine modified urchin-like titanate nanomicrospheres, which are denoted as PDA-UTMS.

2. The method for preparing the polydopamine-modified sea urchin-shaped titanate nanosphere adsorbent as described in claim 1, characterized in that, In the step (1), 2 g of P25 is placed into 40 mL of a 10-15 M NaOH aqueous solution, ultrasonic stirring is performed for 5-10 min, then the solution is transferred into a polytetrafluoroethylene-lined stainless steel reaction kettle and sealed; the reaction kettle is placed into an oven, and heating treatment is performed at 100-120 DEG C, after the reaction is completed, the reaction kettle is naturally cooled in air, a sodium titanate nanotube precipitate is formed, centrifugation, washing and drying are performed.

3. The method for preparing the polydopamine-modified sea urchin-shaped titanate nanosphere adsorbent as described in claim 1, characterized in that, In the step (2), 0.2 g of sodium titanate nanotubes and 1.5 mL of 30% H2O2 are added into 40 mL of a 0.5-1.5 M NaOH aqueous solution for a solvothermal reaction.

4. The method for preparing the polydopamine-modified sea urchin-shaped titanate nanosphere adsorbent as described in claim 1, characterized in that, In step (4), 10 mL of 0.5-1.5 mg mL -1 of aqueous solution of dopamine is slowly added to a mixture of 50-100 mg of protonated urchin-like titanate nanospheres and 10 mL of 0.1 mg mL -1 of Tris.

5. A polydopamine-modified urchin-like titanate nanomicrosphere adsorbent, characterized in that, The polydopamine modified urchin-like titanate nanomicrosphere adsorbent is prepared by using the preparation method in any one of claims 1-4.

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